Pressure reducing valve



March 20, 1951 c. B. LEAcH PRESSURE REDUCING VALVE Filed Feb. 2, 1944 Patented Mar. 20, 1951 L Il".

UNIT-Ep v,sri-rms .PRESSURE REDUCING VALVE Clayton B. Leach, Pontiac, Mich., assignor to. General Motors Corporation, Detroit, Mich., a

corporation of Delaware I il-*Application February 2, 1944, Serial No. 520,721

The present invention is the result of an attempt to develop an improved pressure reducing valve. It has been designed to handle a reduction of pressure from about 2800 pounds per square inch prevailing at a pressure source to ai; 5 pressure of about 400 pounds perv square inch Y which is to be used.

Y It has been customary in the past to use a spring tending normally to open the passage of the fluid medium as it moves from its high pres- `.10

j'sure source to its work performing space, the iiuid c, pressure itself acting against the spring to main- 'tain the passage at such a degree of constriction as to produce the required pressure reduction.

. The herein described novel reducing valve isiizl of the above type. Its mainobject is to overcome the flutter which is an objectionable feature of' 4such valves. Other objects and advantageswill be understood from a reading of thedescription which follows. v i220 On the drawing:

j Fig. 1 is a transverse section through thevi`m' proved reducing valve.

Fig. 2 is a similar section on an enlarged scale of a portion of the device shown by Fig. 1.

j j Fig.- 3 is an explanatory diagram.

Numeral 5 represents the body of the valve. It is formed with a high pressure chamber 1 adapted to be connected to a high pressure source which, for example, may contain air under a pressures() of 2800 pounds per square inch. Numeral 9` t marks a low pressure 'region through which the adjusted pressure escapes to outlets Il, Ila and IIb. The body is formed with a bore I3, the bore extending as at I3 as a passage between cham-35 bers 1 and 9. A hollow valve member I5 is slid` ably mounted in bore I3 and is formed with a iianged head I5' to variably close the passage I3. Into the work end of valve member I5 is threaded a'plug I1 held in position by anut I 9. Extending ,40 from the plug and welded to it is a stem 2 I. The" stem 2l extends through the hollow valve member and into a diaphragm chamber 23 at the remote end oi the body 5. Within the flange I 5' of valve I5 are apertures 25 affording communica- Y45 tion between the low pressure region 9l and the diaphragm chamber 23 by way of the hollow valve member.

Seated against the end of the body 5 is a disk 21. An elongatedv cap 29 is threaded over the .50 end ofthe body and the disk 21 is gripped between the cap and the body. A composition jdiaphragm" 3| is seated within the diaphragm chamber. on a shoulder of the body. A Belleville springtlies adjacent the composition diaphragm 55 s claims. (o1. so-zs) 3l. Its outer periphery engages an annular abutment on disk 21. At their inner openings, both the elements 3| and 33v contact shoulders ona head 35 which lies within the diaphragm chamber and to which the stem 2I is welded. From the head 35 an `integral .threaded spindle extends through disk 21 and into, the cap 29. A11 abutment 31 is threaded on the spindle and it is adapted to contactthe disk 21., The abutment 31 is held by va nut 39." Silidable in thereduced constructed as to'havfa positive rate of about 965: pounds per inch," This' spring rate prevails throughout the working rangeV of the device. '.It

is anknown characteristic of a Belleville spring that the relationv of its cone height to the thickness ofrits material'may be such as to give ita vzero or a negative rate througha predetermined range of action. The present Belleville spring is so constructed and preloaded that throughout its working range' ithas a negative rate 'of about 965 pounds perinch. v

In operation as the uid pressure from the source 1 passes into space 9 and through apertures 25, it tends to flattenthe Belleville spring and'to compress the coilspring thus lifting abutment 31 from the disk 21 and tending to close the gap at I5 and thus eiecting the required pressure reduction for the uid medium passing through outlets II, Ila and IIb.' 'There is effected a balance such that the air pressure opposing the spring pressure maintains the'resultant reduced pressure to within a very few pounds per square inch. y

The important feature of the invention is best shown by the diagram where the coil spring is shown as acting with its characteristic uniform positive rate through and beyond the working range. The Belleville spring supplements the coil spring but throughout the working range it has a negative rate which offsets the positive rate of the coil spring giving a substantially zero rate to the combined springs, by which is meant that, throughout the working range the valve, as it moves to and fro; is subject to a uniform spring action and the troublesome utter is avoided. It will be evident from the drawing that in'installation the Belleville spring is given a preload such that those parts of its movement having a positive .Tate are outside the range oi valve operation.

I claim:

1. In a pressure responsive valve, a body having a high pressure region, a low pressure region, a passage therebetween, a valve member movable on said body, means on said valve member to restrict said passage, pressure responsive means constructed and arranged to be responsive to the pressure in one of said regions and directly connected to said valve to move said valve member in one direction, spring means directly connected to said valve member to move the valve member in the opposite direction, said springs mean including a rst spring having a positive load-deection rate Within the range of valve actuation and a second spring acting in parallel with the first spring and having a negative load-deflection rate substantially equal to the rate of said iirst spring within the range of valve actuation.

2. The invention dened by claim 1, said second spring being a Belleville Washer.

3. In .a pressure responsive valve, a valve body having a passage therethrough, a valve member movable in said body, means on said valve mem- `ber to restrict said passage, a chamber communicating with said passage, said chamber having a iiexible wall comprising a diaphragm and a negative load-deflection rate spring, means connecting said spring to said valve member, and a positive load-deiiection spring operatively connected tosaid valve member acting in parallel with said first spring, and the rates of said springs being substantially equal within the range of -valve actuation. s A

4. A pressure responsive valve having a bodyv -ticn extending into said conduit to engage said seat, a slidable seal between the walls of said chamber and said valve member, a passage in said valve member connecting said conduit with said chamber -beyond said valve member, a diaphragm and a Belleville spring constituting an end Wall of said chamber, said spring being connected to said valve member, and being biased r to oppose the fluid pressure in said chamber, said Belleville spring having a negative load-deiiection rate in the Aoperative range of said valve, a second Vspring connected to said valve member vand acting in parallel with Asaid Belleville spring and having a positive load-deflection rate in "the operative range, the rates 'of said springs being substantially equal within Ithe range of valve actuation.

5. In a pressure responsive valve, av body having ya high pressure region, a low pressure region, a passage therebetween, a valve member movable 'on said body, :means on said valve member to restrict said passage, pressure `responsive means constructed and arranged to be responsive to the pressure 'in one of said regions and directly connected to said valve to move said valve member in one direction, spring means directly connected to said valve 'member to 'move the valve member in the opposite direction, said spring means including ta first spring having a `positive load-deection rate within the range of valve actuation Yand a second spring acting in parallel with the rst spring and having a negative load- -deiiection rate within the range of valve actuation, said spring means having a load-deflec- 4 tion rate of substantially zero, and said second spring having a negative load-deiiection rate substantially equal to the positive load-deflection rate of the iirst spring.

6. In a pressure responsive valve, a body having a high pressure region, a low pressure region,

s a passage therebetween, a valve member movable on 'said body, means on said valve member to restrict said passage, pressure responsive means constructed and arranged to be responsive to the pressure in one of said regions and directly connected to said valve to move said valve member in one direction, spring means directly connected to said valve member to move the valve member in Vthe opposite direction, said spring means including a rst spring having a positive load-deiiection rate within the range of valve actuation and a second spring acting in parallel with the rst spring and having a negative loaddeflection rate substantially equal to the rate of said first spring within the range of valve actuation and a portion of said spring means engaging said pressure responsive means.

7. In a pressure responsive valve, a valve body having a passage therethrough, a valve movable in said body, means on said valve member to restrict said passage, a chamber 'communicating with said passage, said chamber having a iiexible wall comprising a diaphragm and a negative load-deflection spring, means yconnecting said spring to said valve member, and a positive load-deiiection spring operatively connected to said valve member Vacting in parallel with said first spring, the rates ofsaid springs being substantially equal within the lrange of valve operation, and said negative load-deflection spring comprising a Belleville washer. l

8. In a pressure responsive valve, a valve body having a passage therethrough, a valve movable in said body, means on said valve member to restrict said passage, a chamber communicating with said passage, said chamber having a flexible wall comprising a pressure responsive means and a negative load-deflection spring, means connecting said spring to said valve member, and a positive load-deection spring operatively connected to said valve member acting in parallel with said iirst spring, the rates of said springs lbeing substantially equal within the range of valve operation. Y Y

CLAYTON B. LEACH.

REFERENCES CITED UNITED STATES PATENTS V Number Name Date u 65,254 Meggenhofen May 28, 1867 94,748 Holly Sept. 14, 1869 219,625 Dickey sept. 16, 1879 627,390 Cash June 20, 1899 646,064 Bayis 1 Mar. 27, 19Qo 1,107,612 Hodge Aug. 18, 1914 1,178,802 Hamlin Apr. 11, 1916 1,984,792 Ford Dec. 18, 1934 2,013,369 Turner Sept. 3, 1935 2,137,025 Niesemann Nov. 15, 1938 2,308,475 Fawkes Sept. 14, 1943 FOREIGN PATENTS Number Country Date Great Britain 1 Mar. 28, '1911 

